1. Field of the Invention
The present invention is directed to a decoupling element for a fuel injection device.
2. Description of Related Art
A fuel injection device known from the related art is shown as an example in FIG. 1, in which a flat intermediate element is provided on a fuel injector, which is installed in a mounting hole of a cylinder head of an internal combustion engine. Such intermediate elements having the shape of a flat washer are placed as support elements on the shoulder of the mounting hole of the cylinder head in a known way. With the aid of such intermediate elements, manufacturing and installation tolerances are compensated for and a mounting free of lateral forces is ensured even if the fuel injector is slightly inclined. The fuel injection device is suitable in particular for use in fuel injection systems of mixture-compressing, external-ignition internal combustion engines.
Another type of a simple intermediate element for a fuel injection device is already known from published German patent document DE 101 08 466 A1. The intermediate element is a washer having a circular cross section, which is situated in an area in which both the fuel injector and the wall of the mounting hole in the cylinder head run in the shape of a truncated cone and is used as a compensation element for the mounting and support of the fuel injector.
More complicated intermediate elements for fuel injection devices, which are significantly more complex to manufacture, are also known, inter alia, from published German patent document DE 100 27 662 A1, published German patent document DE 100 38 763 A1, and published European patent document EP 1 223 337 A1. These intermediate elements are distinguished in that they all have multipart or multilayer constructions and are to partially take over sealing and damping functions. The intermediate element known from published German patent document DE 100 27 662 A1 includes a main body and a carrier body, in which a sealing means is inserted, which is penetrated by a nozzle body of the fuel injector. A multilayer compensation element is known from published German patent document DE 100 38 763 A1, which is composed of two rigid rings and an elastic intermediate ring sandwiched between them. This compensation element allows both tilting of the fuel injector to the axis of the mounting hole across a relatively large angular range and a radial displacement of the fuel injector out of the central axis of the mounting hole.
An intermediate element which is also multilayered is also known from published European patent document EP 1 223 337 A1, this intermediate element being assembled from multiple flat washers, which are made of a damping material. The damping material made of metal, rubber, or PTFE is selected and designed in such a way that noise damping of the vibrations and noises generated by the operation of the fuel injector is made possible. The intermediate element must include four to six layers for this purpose, however, in order to achieve an intended damping effect.
To reduce noise emissions, U.S. Pat. No. 6,009,856 additionally proposes to enclose the fuel injector using a sleeve and to fill the resulting intermediate space with an elastic, noise-damping compound. This type of noise damping is very complex, difficult to install, and expensive, however.